Method of producing water-soluble crystalline aluminum formate and product obtained thereby.



TINTTED STATES @FFICE.

FRITZ ouann, or BERLIN, GERMANY, ASSIGNOR TO THE FIRM or JOHANN A.

* -wfirrme, or BERLIN, GERMANY.

METHOD PRODUCING WATER-SOLUBLE CRYSTALLINE ALUMINUM FORMATE'AND PRODUCT OBTAINED THEREBY.

1,@3@,74t7. No Drawing.

Germany, residing at Berlin, in the Empire of Germany, have invented a new and useful Method of Producing Water-Soluble Crystalline Aluminum Formate and Product Obtained Thereby, of which the following is a specification.

My invention relates to a water soluble crystalline aluminum formate which is particularly suit-able in the form of tablets for the preparation of disinfecting aqueous solutions.

Heretofore aluminum formate has been known and has been commercially available only in the form ofits aqueous solutions. The literature contains no description of the production of a solid crystalline watersoluble aluminum formate. Thus by decomposing equivalent quantities of barium formate with all inum sulfate and evaporating the filtrate from the barium sulfate only a a gummy inass is obtained (see Schmidt, Pharm. Okemz'c, vol. II, part 1,

p. 353, 4th ed., published by Vieweg 1901).

Now I havediscovered that out of a solution of Wet aluminum hydroxid in 95% formic acid, there is precipitatedon careful evaporation on the water bath, a crystalline water-soluble salt, with a content of 11.6% of aluminum. From aqueous solutions this compound ,cannot be again obtained by recrystallizing as is possible, for instance, with the basic chromlum formate cnHooo acro-100 0 on+n o num and soluble in cold water can also be obtained if the aqueous solution of aluminum formate obtainable in commerce is evaporated with the addition'of concentrated formic acid to the beginning of the formation of a crust, and is then lei" to crystallize at a temperature of from 25 to 30 degrees C. The crystalline cake can be freed from adherent traces of free formic acid by washing with ether.

Specification of Letters Patent.

Application filed July 25, 1910. Serial No. 573,769.

Patented June 2 5, 1912.

The easily soluble non-hygroscopic and permanent salts of the present invention have application for pharmaceutical purposes. i

A soluble solid aluminum acetate cannot be obtained in this manner.

I claim:

1. The method of producing a watersoluble crystalline aluminum formate which comprises evaporating a solution of aluminum formate in the presence of an excess of formic acid and allowing the same to crystallize. v

2. The method of producing a water soluble crystalline aluminum formats which comprises preparin a concentrated solution of aluminum ormate, evaporating to incipient crystallization in the presence of an excess of formic acid, and a lowing the same to crystallize. k

The method of producing a watersoluble crystallinealuminum formate which comprises preparing, a concentrated solution of aluminum formats, evaporating to incipient crystallization in the presence of an excess of formic acid, and crystallizing at a temperature of'25 to 30 C.

4. The hereindescribed method of producing a water-soluble crystalline aluminum formate which comprises dissolving wet aluminum.hydroxid in concentrated formic acid in excess to form a concentrated solution Ofaluminum formate in formic acid, evaporating to the formation of a crust and ggy stillizing at a temperature .of 25 to firIn the manufacture of aluminum formate the process which comprises crystallizing aluminum formate from its solutions in the presence of an excess of formic acid. I

6. As a new product a stable crystalline non-hygroscopic compound of aIummum' and formic acid, soluble in water.

In testimonv whereof I aflix my signature in presence 0 two witnesses.

FRITZ QUAIiE. Witnesses:

Max LEMCKE, Louis VANDORY. 

